Currently (rev. 190872), we sometimes change the function body when
generating inlining summaries, specifically at some point in
loop_optimizer_init, which is called to get BB loop depths and loop
This happens for example when compiling function MAIN__ of
Summary generations of IPA passes should not modify function bodies,
pass manager should do all such body changing analyses instead.
More information in
http://gcc.gnu.org/ml/gcc-patches/2012-09/msg00148.html and other
messages in that thread.